Honestly, the first thought that came to mind was making sure you had the homeworlds of most of the established races in there. Homeworlds of the Zabrack and Echani come to mind, as they're two of my favorite races, and not widely known. Iridonia, home of the Zabrak is volcanic, so you have some variance there, and as for ice planets. Rhen Var wasn't in the last version:http://starwars.wikia.com/wiki/Rhen_Var
I'm going to spitball some with the lore on these, but here goes:
Name: Rhen Var
Planetary Government: (imperial leanings)
History: Site of an Imperial outpost, speculated to be used for training troops for cold environments.
Unique features: Ruins of an ancient civilization
Climate: Temperate climate: sweeping plains, scattered mountain ranges, and low-key cities. (I heard somewhere it resembles Chandrila)
Planetary Government: Matriarchal, Clan based confederation
History: An often overlooked core world, Eshan is the homeworld of the Echani. A unique humanoid race with completely identical features. Echani have therefore learned to identify each other use micro-expressions and body language, and found hand-to-hand combat one of the sincerest and most insightful expressions of these things. It is a widely held Echani belief "you cannot truly
know someone until you have fought them in combat" and make it a part of their social interaction. With combat as an art-form, Echani combat techniques are in a league of their own, anticipating their opponent's moves whole minutes
ahead of their advent, like a game of chess. This skill, combined with their apparent blindness to the force, made them emperor Palpatine's ideal choice for his royal bodyguards during the reign of the Galactic Empire.
Capital City: Unknown
Unique features: Possible location of the Handmaiden order that served the Jedi in the Old republic days.
Races: Zabrak, Triz, Zur, Reek (transplanted)
Climate: Harsh, Volcanic planet with Acid pools and seas, and deep, windy canyons with farmable land
Planetary Government: Dictatorship
History: Iridonia was the homeworld of the Zabrak species. Due to the harsh living conditions, the Zabrak developed into a hardy, resilient species. In like manner, their engineering and survival gear is renowned for being similarly resilient under the harshest conditions, making it a sought after commodity in many parts of the galaxy.
Capital City: Malidris
Unique Features: Sith Academy
Now, I will note you say "cool". But now that I see frozen worlds are on your "typical" list, I'm not sure if that's what you're looking for. Are you meaning like a rainy planet?